Clinical Characteristics and Influencing Factors on Prognosis of Patients with Acute Myocardial Infarction Associated by Low T3 Syndrome

SONG Wei; ZHANG Zhi-fei

doi:10.3969/j.issn.1002-3429.2017.08.020

Abstract：Objective To investigate clinical characteristics and influencing factors on prognosis of patients with acute myocardial infarction associated by low triiodothyronine (T3) syndrome.Methods A total of 260 patients with acute myocardial infarction admitted during June 2012 and June 2014 were divided into euthyroidism group (n=150) and low T3 syndrome group (n=110) according to results of thyroid function and cardiac ultrasound examination.In two groups, clinical characteristics and incidence rate of cardiovascular events during follow-up were compared, and influencing factors on prognosis of patients with acute myocardial infarction were analyzed.Results Compared with those in low T3 syndrome group, in euthyroidism group, values of age, total cholesterol, low-density lipoprotein cholesterol, hospital stay and assisted continuous positive airway pressure rate were significantly lower;serum total triiodothyronine (TT3), free triiodothyronine (FT3) and left ventricular ejection fraction levels were significantly higher;incidence rates of recurrent myocardial infarction, new heart failure, sudden cardiac death and malignant arrhythmia during the follow-up were significantly lower (P<0.05).Univariate log-rank regression analysis showed that age, serum levels of FT3, left ventricular ejection fraction, history of hypertension and hyperlipidemia were influencing factors on prognosis of patients with acute myocardial infarction (P<0.05).Multivariate Cox proportional hazards model analysis showed that age (≥65 years old), serum FT3 level (<5.2 pmol / L) and score of left ventricular ejection fraction (<50%) were independent factors on prognosis for acute myocardial infarction (P<0.01).Conclusion Serum FT3 level has a certain relationship with prognosis of patients with acute myocardial infarction, and the incidence rate of cardiovascular events in acute myocardial infarction patients with serum FT3<5.2 pmol/L is increased, and then the prognosis is poor.